Homalocenchrus Mieg, nom. rej.

Perennial aquatic or marsh plants, stoloniferous or rhizomatous. Culms slender, lower part creeping or floating, upper part erect or ascending, many-noded, nodes swollen, hairy. Leaf blades mainly cauline, linear-lanceolate; ligule papery. Inflorescence a lax panicle, branches often simple and racemelike, pedicels short. Spikelets with one floret, elliptic to narrowly oblong, straighter on one side, strongly laterally compressed, disarticulating from pedicel; glumes absent; lemma boat-shaped, keeled, firmly papery or leathery, prominently 5-veined, marginal veins interlocking with marginal veins of palea, keel scabrid to pectinate ciliate, apex acute or beaked, awnless; palea resembling lemma but narrower, 3-veined, keel ciliate. Stamens 1, 2, 3, or 6. Caryopsis oblong, embryo 1/3 length of caryopsis, hilum linear. x = 12.

This genus is distinguished from Oryza only by the absence of sterile lemmas.

About 20 species: tropical and warm-temperate regions of the world; four species in China.